title: DNA repair gene XRCC1 polymorphisms and head and neck cancer risk: an updated meta-analysis including 16344 subjects.
abstract: BACKGROUND
  DNA repair gene X-ray repair cross complementing group 1 (XRCC1) plays an important role in the maintenance of the genomic integrity and protection of cells from DNA damage. Sequence variation in XRCC1 gene may alter head and neck cancer (HNC) susceptibility. However, these results are inconclusive. To derive a more precise estimation of the relationship between XRCC1 polymorphism and HNC risk, we undertook a meta-analysis involving 16,344 subjects.
  
  
  METHODS
  A search of the literature by PubMed, Embase, Web of Science and China National Knowledge Infrastructure was performed to identify studies based on the predetermined inclusion criteria. The odds ratio (OR) with 95% confidence interval (CI) was combined using a random-effects model or a fixed-effects model.
  
  
  RESULTS
  Twenty-nine studies consisting of 6,719 cases and 9,627 controls were identified and analyzed. Overall, no evidence of significant association was observed between XRCC1 Arg194Trp, XRCC1 Arg280His, XRCC1 Arg399Gln genotypes and the risk of HNC in any genetic models. Subgroup analyses according to ethnicity, tumor site, publication year, genotyping method also detected no significant association in any subgroup, except that oral cancer was associated with Arg194Trp variant in recessive model. Furthermore, no significant effect of these polymorphisms interacted with smoking on HNC risk was detected but Arg194Trp homozygous variant.
  
  
  CONCLUSIONS
  In conclusion, this meta-analysis suggests that the XRCC1 Arg194Trp, Arg280His and Arg399Gln polymorphism may not involve in HNC susceptibility. Further studies about gene-gene and gene-environment interactions in different populations are required.
authors.affiliation: Department of Plastic Surgery, The second Hospital of Anhui Medical University, Hefei, China.
authors.forename: Yin
authors.initials: Y
authors.lastname: Lou
authors.forename: Wen-jia
authors.initials: WJ
authors.lastname: Peng
authors.forename: Dong-sheng
authors.initials: DS
authors.lastname: Cao
authors.forename: Juan
authors.initials: J
authors.lastname: Xie
authors.forename: Hong-hong
authors.initials: HH
authors.lastname: Li
authors.forename: Zheng-xuan
authors.initials: ZX
authors.lastname: Jiang
mesh_terms: D004260:DNA Repair / Q000235:genetics*; D004268:DNA-Binding Proteins / Q000235:genetics*; D020022:Genetic Predisposition to Disease; D006258:Head and Neck Neoplasms / Q000235:genetics*; D006801:Humans; D011110:Polymorphism, Genetic; D000076105:X-ray Repair Cross Complementing Protein 1
chemical_list: D004268:DNA-Binding Proteins; D000076105:X-ray Repair Cross Complementing Protein 1; C000619371:XRCC1 protein, human